Arxiv Test is failing with the search phrase, because both queries return the same result.

@DominikVoigt In ArxivTest supportsPhraseSearch(), both queries return the same result. Maybe you can take a look at that

      List<BibEntry> resultWithPhraseSearch = fetcher.performSearch("au:\"Tobias Diez\"");
        List<BibEntry> resultWithOutPhraseSearch = fetcher.performSearch("au:Tobias Diez");

• Change in CHANGELOG.md described (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked documentation: Is the information available and up to date? If not created an issue at https://github.com/JabRef/user-documentation/issues or, even better, submitted a pull request to the documentation repository.